Generally, in order to control the position and posture on a three-dimensional plane, a robot with a serial structure has been widely used in surgery using a robot. However, recently, various kinds of parallel-structured robots have been developed and used in contrast to the serial structure.
Such a parallel-structured surgical robot has various advantages over a serial-structured surgical robot. The first advantage is that the inertia mass of the moving part is reduced as compared with the serial-type surgical robot, thereby increasing speed and acceleration of a machine. A second advantage is that a base platform and a moving platform are connected by a plurality of actuators, so that each of the actuators receives only tensile and compressive forces instead of bending forces, thereby increasing mechanical stiffness. The third advantage is that error of each of the actuators is reflected on the moving platform on average, so that accuracy is improved compared with a serial-type surgical robot in which errors are accumulated.
However, when a degree of freedom of the general parallel-structured surgical robot is increased, the number of actuators corresponding to the increased degree of freedom is required to be installed between the base platform and the moving platform. Thus, when parallel-structured robots with more than 4 degrees of freedom are manufactured with the increase of manufacturing cost, the size of the robots may be increased, which may cause a problem of being limited in installation and operation space. In addition, when a strong load is applied to an actuator disposed between the base platform and the moving platform, especially an actuator for translational motion, the structural stability may be adversely affected.